Method for the uniform dressing of contact rolls



June 16, 1953 c, BOEHM 2,641,872

METHOD FOR THE UNIFOBM DRESSING 0F CONTACT ROLLS Filed April 2, 1951 Patented June 16, 1953 METHOD FOR THE UNIFORM DRESSING OF CONTACT ROLLS Charles H. Boehm, Detroit, Mich., assignor to Houdaille-Hershey Corporation, Detroit, Mich., a corporation of Michigan Application April 2, 1951, Serial N 0. 218,751

1 The present invention relates to a method and to an apparatus for the uniform dressing or trueing of contact rolls such as those employed in polishing machines.

The method of the present invention will be applicable to the surface finishing of cylinders generally, and particularly to the surface finishing of resiliently covered rollers. One of the most important applications of the method and apparatus of the present invention is in connection with polishing machines in which substantially flatyworkpieces to be polished are fed between an abrasive surfaced contact roller and a backing or idler roll, commonly known as a billy roll.

In many conventional polishing machines, the

workpiece is fed by means of positively driven feed rollers between a driven resiliently surfaced contact roll and an idler roll. An endless abrasive coated web is trained around the driven contact roll, and the contact roll is driven at a relatively high velocity so that the polishing is effected by pressure contact between the abrasive paper trained about the contact roll and the surface of the workpiece. 7 After prolonged polishing operations,-the surface of the contact roll, which is ordinarily of rubber or other resilient material, becomes deformed, or distorted, and therefore out of true surface alignment with the idler roll. Since efficient polishing requires that the contact roll be in true surface alignment with the backing or idler roll, the deformation or distortion of the surface of the contact roll after prolonged use necessitates the shut-down of equipment and resurfacing of the contact roll.

An object of the present invention is to provide means for periodically finishing the surface of a roll to its proper configuration.

Another object of the present invention is to provide a method for dressing. or trueing a resiliently covered contact roll in a polishing apparatus to insure its proper alignment idler roll in the assembly.

Still another object of the present invention is to provide a modified polishing apparatus in which periodic dressing or resurfacing of a contact roll is accomplished.

'Still another object of the present invention is to provide an apparatus for insuring the correct surface alignment between the resiliently covered contact roll and the coacting idler roll in a polishing assembly.

The method of the present invention consists in dressing or trueing a roll by bringing into tangential contact with the roll surface a rigidwith the 2 Claims.

ly backed, substantially fiat surface having abrasive characteristics and moving the surfaces relative to and in pressure contact with each other at a differential linear speed. In one form of the invention, periodic dressing of the contact roll is accomplished by removing the abrasive belt from about the contact roll, applying an abrasive surface to a substantially flat workpiece, and then feeding the abrasive coated workpiece between the resiliently covered contact roll and the idler roll. The peripheral velocity of the driven contact roll is ordinarily substantially higher than the linear velocity of the abrasive coated workpiece, so that upon contact of the abrasive surface with the contact roll the surface of the roll is dressed accurately by the removal of surface irregularities which have occurred dur ing previous polishing operations.

A further description of the present invention is made in connection with the attached sheet of drawings in'which:

On the drawings Figure 1 is a fragmentary view of a polishing apparatus with parts in elevation, illustrating the apparatus in position to effect polishing of a substantially flat piece of metallic stock;

Figure 2 is a slightly enlarged view of the assembly illustrated in Figure 1, illustrating the condition of the apparatus during the resurfacing or trueing of the contact roll;

Figure 3 is a fragmentary view of the abrasive coated workpiece used to resurface the resiliently covered roll, with portions thereof broken away; and

Figure 4 is a fragmentary cross-sectional view taken substantially along the line IV--IV of Figure 3.

As shown on the drawings:

The system of Figure 1 includes a more or less conventional polishing assembly and illustrates the position of the elements during the polishing operation. In that assembly, reference numeral l0 denotes a frame assembly which carries a drive motor! I. A shaft I 2 of the motor carries a sprocket [3, about which is trained a chain M for driving a sprocket wheel l5 on a resiliently covered contact roll IS.

The frame member Ill also supports an idler tensioning roller [1 by means of a pivotally movable shaft l8, and a second idler roller I9 at the top of the frame member H]. An abrasive material, such as a paper web 20 containing abrasive particles embedded in its outer surface, is trained around the contact roll I6 and the idler rollers I 1 and IS in the form of an endless loop. The proper tension on the web 20 is supplied by adjusting the position of the idler roller I 1 by varying the angular position of the arm [3,

In operation, substantially fiat plates of metal 22 are fed between the moving abrasive web 23 and a rigidly journaled backing or idler roll 23. Suitable means 42 are provided for adjusting and maintaining the desired contact pressure between the abrasive web 29 and the plates 22. Each plate 22 is fed positively between the contact roll 16 and the idler roll 23 with a predetermined linear velocity by means of a pair of coacting pinch rolls 25 and 26 preceding the contact roll 16, and a pair of pinch rolls 2'! and 28 beyond the contact roll assembly. The pair of pinch rolls 25 and 26 is driven by a motor 30 through a chain and sprocket drive 3! and intermeshing sprocket gears 32 carried by the pinch rolls 25 and 2B. In a similar manner, the pinch rolls 2'! and 28 are positively driven by motor 34 through a chain and sprocket wheel 35 and intermeshing sprocket gears 36.

After prolonged operation of the assembly illustrated in Figure 1, the surface of the contact roll l6 becomes somewhat irregular and does not remain in correct alignment with the idler roll 23 to insure perfect flat polishing of the workpiece 22. In accordance with the present invention, when this condition occurs, the surface of the contact roll it is refinished as illustrated in the system of Figure 2. For purposes of clarity, the various drive mechanisms have been eliminated from the showing of Fig* ure 2, since it Will be understood that they operate in an identical manner to that described in connection with Figure 1.

When the contact roll i6 is to be refinished, the abrasive web 20 is removed from the assembly shown in Figure 1, leaving the resiliently covered contact roll 16 exposed. At such time, in place of the usual flat workpiece that is to be polished, I may use the same workpiece but provide it with an abrasive surface coating to make a composite workpiece 22a, such as illustrated in FiguresB and 4. As a matter of convenience, a portion of the abrasive web 20 removed from the polishing machine can be employed to make up the composite abrasive workpiece, or, if desired, a new strip of abrasive paper can be used.

As shown in Figure 3, an abrasive covered as that of an uncoated workpiece plus the thickness of the abrasive strip 20, the setting of the rolls I8 and 23 may be left unchanged and still provide the same pressure contact between the surface of the roll 56 and the abrasive surface of the composite workpiece during dressing as obtained during polishing. The linear velocity of the abrasive coated strip is substantially less than the peripheral velocity of the driven contact roll I6, so that upon passage of the abrasive coated member against the surface of the contact roll Hi the abrasive paper 40 eifectively abrades the resilient coating on the contact roll l6 and thus trues the surface of the coating. The abrasive coated composite workpiece may be passed through the roll assembly as many times as is necessary to effect the trueing operation, or a single pass may be found sufiicient.

At the end of the roll dressing cycle, the abrasive web 20 is again trained about the contact roll [6 and the idler rollers I! and 19, in the manner indicated in Figure 1, for further polishing operations.

From the foregoing, it will be appreciated that the present method provides a continuous means for resurfacing a contact roll in a polishing apparatus. The method is convenient and economical to use since it requires no substantial modification of existing polishing apparatus and can be carried out by unskilled help. Furthermore, the presently described system insures accurate trueing of the contact roll for a particular type of workpiece to be polished because, in effect, the workpiece is used as a gauge during the resurfacing of the contact roll.

It will be understood that modifications and variations may be efiected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In a polishing operation wherein a substantially flat workpiece is polished by passage between a driven abrasive surfaced contact roll and an idler roll, the steps of dressing said roll comprising periodically removing said abrasive surface from said contact roll, applying an abrasive surface to a plane member having the thickness of said workpiece and passing said plane member between said contact roll and said idler roll with the abrasive surface of said plane member in pressure contact with said contact roll to thereby effect abrasion of said contact roll.

2. In a polishing operation wherein a substantially flat workpiece is polished by passage between a driven abrasive surfaced contact roll and an idler roll, the steps of dressing said roll comprising periodically removing said abrasive surface from said contact roll, applying an abrasive surface onto a plane member having the thickness of said workpiece, and passing said plane member between said contact roll and said idler roll with the abrasive surface of said plane member in pressure contact with said contact roll while rotating said contact roll at a higher peripheral velocity than the linear velocity of said plane member to thereby effect abrasion of said contact roll.

CHARLES H. BOEHM.

References Cited. in the file of this patent UNITED STATES PATENTS Number Name Date 439,819 Horvieson Nov. 4, 1890 660,618 Bosworth Oct. 30, 1900 977,923 Barker Dec. 6, 1910 980,052 Blerney et a1 Dec. 27, 1910 1,763,561 Mulder June 10, 1930 1,918,483 Munday July 18, 1933 2,162,279 Herchenrider June 13, 1939 

